Computers commonly use hard disc drives to store large amounts of data in a form that can be readily accessed by a user. A disc drive generally includes a stack of vertically spaced magnetic discs that are rotated at a constant high speed by a spindle motor. The surface of each disc is divided into a series of concentric, radially spaced data tracks in which the data are stored in the form of magnetic flux transitions. Typically, each data track is divided into a number of data sectors that store data blocks of a fixed size.
Data are stored and accessed on the discs by an array of read/write heads ("heads") mounted to a rotary actuator assembly, or "E-block." Typically, the E-block includes a plurality of actuator arms which project outwardly from an actuator body to form a stack of vertically spaced actuator arms. The stacked discs and arms are configured so that the surfaces of the stacked discs are accessible to the heads mounted on the complementary stack of actuator arms.
Head wires included on the E-block conduct electrical signals from the heads to a flex circuit, which in turn conducts the electrical signals to a flex circuit bracket mounted to a disc drive basedeck. For a general discussion of E-block assembly techniques, see U.S. Pat. No. 5,404,636 entitled METHOD OF ASSEMBLING A DISK DRIVE ACTUATOR, issued Apr. 11, 1995 to Stefansky et al., assigned to the assignee of the present invention.
The actuator body pivots about a cartridge bearing assembly which is mounted to the disc drive housing at a position closely adjacent the outer extreme of the discs. The actuator assembly includes a voice coil motor which enables the actuator arms and the heads attached thereto to be rotated about the cartridge bearing assembly so that the arms move in a plane parallel to the surfaces of the discs to selectively position a head over a preselected data track.
The voice coil motor includes a coil mounted radially outwardly from the cartridge bearing assembly, the coil being immersed in the magnetic field of a magnetic circuit of the voice coil motor. The magnetic circuit comprises one or more permanent magnets and magnetically permeable pole pieces. When current is passed through the coil, an electromagnetic field is established which interacts with the magnetic field of the magnetic circuit so that the coil moves in accordance with the well-known Lorentz relationship. As the coil moves, the actuator body pivots about the pivot shaft and the heads move across the disc surfaces.
Each of the heads is mounted to an actuator arm by a flexure which attaches to the end of the actuator arm. Each head includes an interactive element such as a magnetic transducer which either senses the magnetic transitions on a selected data track to read the data stored on the track, or transmits an electrical signal that induces magnetic transitions on the selected data track to write data to the data track. Air currents are caused by the high speed rotation of the discs. A slider assembly included on each head has an air bearing surface which interacts with the air currents to cause the head to fly at a short distance above the data tracks on the disc surface.
There is a generally recognized trend in the industry to decrease the power requirements of modern disc drives. It has been determined that air turbulence within the disc drive creates drag on the discs, thereby having a negative affect on the power requirements of the disc pack spindle motor. Simply stated, the more air turbulence inside the disc drive, the more power it takes to spin the disc pack. Because discs are being turned at ever increasing revolutions per minute, the problem of air turbulence in the disc drive becomes even more significant.
Prior art actuator arms have had blunt leading edges. The air flow caused by the high speed rotation of the discs within the drive runs strikes against the blunt leading edges of the actuator arms, creating turbulence within the drive. This turbulence results in drag on the discs and increased power consumption by the disc pack spindle motor. Thus, there is a need for an improved technique for reducing air turbulence within the disc drive.
The present invention provides a solution to this and other problems, and offers other advantages over the prior art.